Abstract:

Xanthine (Xan) and oxanine (Oxa) are the major deamination products of guanine formed by the treatment with nitrogen oxides (e.g., NO and HNO2). In this study, 2'-deoxyribonucleoside 5'-triphosphates of Xan and Oxa were prepared by the NaNO2 treatment of dGTP. These modified nucleotides were incorporated into oligonucleotides by DNA polymerase reactions. The repair activities of various DNA N-glycosylases for Xan and Oxa were examined using these substrates.